1. Field of the Invention
The present invention relates to a shift register, and more particularly, to a shift register which is capable of stably outputting a scan pulse of a composite waveform in an organic light emitting diode display device.
2. Discussion of the Related Art
In an organic light emitting diode display device, there may be deviations among driving currents applied to respective pixels, and a number of transistors are integrated inside of each pixel to prevent such deviations.
This display device includes a shift register for sequentially generating a number of control signals to drive the transistors.
Such a conventional shift register employs a multiplexer structure to output a scan pulse of a composite waveform which consists of two waveforms having different widths and timings.
This structure generates the scan pulse of the composite waveform by switching a fixed, constant voltage externally provided. In this regard, stably outputting the scan pulse may involve increasing the sizes of output transistors which switch the scan pulse, resulting in an increase in the size of the display device.